ME function to move the contents of one inventory into another

api.lua

-- [function] Move items from inv to inv
function microexpansion.move_inv(inv1, inv2)
  local finv, tinv   = inv1.inv, inv2.inv
  local fname, tname = inv1.name, inv2.name

  for i,v in ipairs(finv:get_list(fname) or {}) do
    if tinv and tinv:room_for_item(tname, v) then
      local leftover = tinv:add_item( tname, v );
      finv:remove_item( fname, v );
      if leftover and not( leftover:is_empty() ) then
        finv:add_item( fname, v );
      end
    end
  end
end